Docks and panels are not equivalent. They have different functionality, and as far as I know you would need different applets to put the functions from the system tray on Cairo Dock. You DEFINITELY can't just drag and drop the functions from the top panel to the dock. The best you could do is to auto-hide the top panel.

I do understand that the exact same program will not embed its code in the dock. But are there replacements or work arounds to get this functionality into Cairo-Dock to possibly not require use of the Panel ... is my more precisely worded question.

The indicator apps are tied to the panel and would have to be completely re-written. The source code is there if you wish to contribute your time?

I remember a clock applet available for Cairo Dock, an app to track the virtual desktops, link to a volume control, network connection indicator, app menu, logout and others. You could have very little on the top panel, and some panels will auto-hide.